JP3912718B2 - Flame detector and fire detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flame detector and a fire detector.
[0002]
[Prior art]
In a conventional flame detector installed in a tunnel, a light receiving element is covered with light receiving glass, and the light receiving element receives radiation light emitted by a flame. And since the said light reception glass is easy to get dirty, the degree of the dirt is grasped and existence of a flame is discriminated based on the output signal of a light receiving element, and the degree of dirt of the above-mentioned light reception glass. That is, the conventional flame detector confirms the function of the flame detector using a flame pseudo light source during the test of the flame detector, and appropriately corrects the sensitivity for the contamination of the light receiving glass.
[0003]
[Problems to be solved by the invention]
However, in the above conventional example, when confirming the function of the flame detector and correcting the sensitivity of the flame detector, if external light noise such as light from a revolving light (a revolving light installed in a vehicle) is received The function of the flame detector cannot be properly confirmed, and the sensitivity of the flame detector cannot be corrected appropriately. In other words, since external light such as a rotating lamp has a frequency close to the fluctuation frequency of a fire, there is a problem that receiving external light such as a rotating lamp affects the result of flame detection.
[0004]
In order to solve this problem, the function detection of the flame detector and the correction of the sensitivity of the flame detector may be performed in a time zone in which the vehicle in which the rotating light is installed is less traffic. However, since traffic volume is increasing year by year, the time zone with less traffic volume is gradually shortened. Just considering the time zone, the function of the flame detector can be properly confirmed and the sensitivity of the flame detector can be improved. There is a problem that it is difficult to correct appropriately.
[0005]
By the way, in the conventional flame detector, the gain in the amplifying unit that amplifies the output signal of the light receiving element is always constant, that is, the gain of the amplifier when the light receiving glass is less fouled, the light receiving glass is more fouled. As large as the gain of the amplifier in the case. Therefore, the amplifier has a problem that a large current flows by receiving light, and the power consumption in the amplifier is large.
[0006]
In the present invention, when the function of the flame detector is confirmed and the sensitivity is corrected, the function of the flame detector can be appropriately confirmed even if external light noise such as light from a rotating lamp is received. An object of the present invention is to provide a flame detector capable of appropriately correcting the sensitivity of the flame detector.
[0008]
[Means for Solving the Problems]
In the present invention, a narrow band filter is connected to the flame detection element, and the center frequency of the narrow band filter is changed to a high frequency at the time of a function test of the flame detector, thereby reducing external light noise such as light from a rotating lamp. It is a flame detector that makes it difficult to be affected.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram showing a flame detector FD1 according to the first embodiment of the present invention.
[0012]
The flame detector FD1 includes a light receiving element 11, a switch SW, a fire monitoring narrow band filter 12, an amplifier circuit 13, a smoothing circuit 14, a dirt detection narrow band filter 15, and a fire determination control microcomputer 31. A light emission control circuit 41, a dirt detection light emitting element 42, and a light receiving glass G.
[0013]
The dirt detection light emitting element 42 is installed outside the light receiving glass G, and is disposed opposite the light receiving element 11.
[0014]
The light emission control circuit 41 is a circuit that is controlled by the fire determination control microcomputer 31 and causes the dirt detection light emitting element 42 to emit light.
[0015]
The light receiving element 11 is installed inside the light receiving glass G.
[0016]
The fire monitoring narrowband filter 12 is a filter that has a flame fluctuation frequency characteristic and inputs an output signal of the light receiving element 11.
[0017]
The fire determination control microcomputer 31 is an example of flame determination means for determining the presence of a flame based on the output signal of the fire monitoring narrow band filter 12.
[0018]
The dirt detection narrow band filter 15 has a frequency characteristic different from the flame fluctuation frequency characteristic, and is a filter for inputting an output signal of the light receiving element 11.
[0019]
The fire determination control microcomputer 31 detects the degree of contamination of the light receiving glass G based on the output signal of the contamination detection narrow band filter 15 when the contamination detection light emitting element emits light. It is an example.
[0020]
The switch SW is an example of switching means for switching the supply destination of the output signal of the light receiving element 11 to the fire monitoring narrow band filter 12 or the dirt detection narrow band filter 15, and the switching is controlled by the fire determination control microcomputer 31. Is done.
[0021]
The amplifier circuit 13 amplifies the output signal of the fire monitoring narrow band filter 12 and the output signal of the dirt detection narrow band filter 15.
[0022]
The smoothing circuit 14 is a circuit that smoothes the output signal of the amplifier circuit 13.
[0023]
Next, the operation of the above embodiment will be described.
[0024]
FIG. 2 is a flowchart showing the operation of the above embodiment.
[0025]
First, when the fire determination control microcomputer 31 receives a test control signal from the disaster prevention panel (S1), the switch SW is switched so as to send the output signal of the light receiving element 11 to the dirt detection narrow band filter 15 (S2). . Then, the dirt detection light emitting element 42 is caused to emit light (S3), thereby executing the test of the flame detector FD1 (S4).
[0026]
That is, the fire determination control microcomputer 31 causes the dirt detection light emitting element 42 to emit light via the light emission control circuit 41, and the light receiving element 11 receives the light emission via the light receiving glass G, and the output of the light receiving element 11. The signal passes through the dirt detection narrow band filter 15, is amplified by the amplifier 13, smoothed by the smoothing circuit 14, and sent to the fire determination control microcomputer 31. In the fire determination control microcomputer 31, the degree of contamination of the light receiving glass G is detected.
[0027]
In the above case, since the dirt detection narrow band filter 15 has a frequency characteristic different from the flame fluctuation frequency characteristic, light (noise) from a rotating lamp or the like having a frequency characteristic similar to the flame fluctuation frequency is generated. Therefore, the contamination of the light receiving glass G can be accurately detected. That is, according to the above-described embodiment, the test of the flame detector FD1 is performed without being influenced by the traffic volume (external light noise due to lighting of the traveling vehicle), and the selection of the time zone or the like is not necessary.
[0028]
Further, in the above embodiment, when the dirt of the light receiving glass G is detected, the center frequency of the light emission pulse emitted from the dirt detection light emitting element 42 is higher than the frequency of the light emission pulse emitted when detecting the flame. Since it is high, the light emission pulse width for causing the light emitting element 42 to emit light can be shortened.
[0029]
On the other hand, if the switch SW does not receive the test control signal from the fire determination control microcomputer 31 (S1), the switch SW is switched so as to send the output signal of the light receiving element 11 to the fire monitoring narrowband filter 12 (S5). Fire monitoring is performed (S6).
[0030]
FIG. 3 is a diagram showing the frequency characteristics of the fire monitoring narrow band filter 12 and the frequency characteristics of the dirt detection narrow band filter 15.
[0031]
FIG. 4 is a block diagram showing a flame detector FS2 according to the second embodiment of the present invention.
[0032]
The flame detector FS2 is provided with a pyroelectric element 11 for fire monitoring and a PD 21 for dirt detection instead of the light receiving element 11 and the switch SW in the flame detector FS1, and the pyroelectric element 11 is provided for fire monitoring. The narrow band filter 12, the amplifier circuit 13, and the smoothing circuit 14 are connected, and the PD 21 is provided with a dirt detection narrow band filter 15, an amplifier circuit 13a, and a smoothing circuit 14a. By these, the right side detection part R is comprised and the structure of the left side detection part L is the same as that of the right side detection part R. Further, in the light receiving glass G, a right side detection unit R and a left side detection unit L are provided.
[0033]
Note that the flame detector FD2 is employed when the position of the fire monitoring light receiving element does not exist at an appropriate position of the light receiving glass G, such as when the light receiving glass G is large. The pyroelectric element 11 is an example of a fire monitoring light receiving element that detects radiation from a flame.
[0034]
That is, the flame detector FD2 is installed inside the light receiving glass G, and has a fire monitoring light receiving element 11 that detects radiation from the flame, and a fluctuation frequency characteristic of the flame. A narrowband filter for fire monitoring 12 that inputs a signal, a flame determination means for determining the presence of a flame based on the output signal of the narrowband filter for fire monitoring 12, and a stain detection installed outside the light receiving glass G Frequency characteristic different from the flame fluctuation frequency characteristic, and the dirt detection light-receiving element PD21 installed inside the light-receiving glass G and opposite to the dirt detection light-emitting element 42 The dirt detection narrow band filter 15 for inputting the output signal of the dirt detection light receiving element 21 and the dirt detection light emitting element 42 emit light when the dirt detection light emitting element 42 emits light. Based on the signals, an example of a flame detection device and a dirt degree detecting means for detecting a contamination degree of the light-receiving glass G.
[0035]
FIG. 5 is a circuit diagram showing a fire detector FD3 according to the third embodiment of the present invention.
[0036]
The fire detector FD3 includes a fire detection unit 50, a test light emitting unit 60, and a test light receiving unit 70.
[0037]
The fire detection unit 50 includes a light receiving element 51, amplification units 52 and 52 a, a CPU 53 that determines fire, and a gain switching unit 54.
[0038]
The test light emission unit 60 includes a test light emission control unit 61 and a light emitting element 62 provided outside the light receiving glass G. The light emitting element 62 emits light for measuring the contamination of the light receiving glass G. The light emitting element 62 emits light by controlling the test light emission control unit 61 according to a command from the CPU 53.
[0039]
The test light receiving unit 70 includes a light receiving element 71 and an amplification unit 72. The light receiving element 71 receives light emitted from the light emitting element 62, and the amplification unit 72 amplifies the output signal of the light receiving element 71 and sends it to the CPU 53.
[0040]
FIG. 6 is a diagram illustrating the relationship between the contamination rate of the light receiving glass G in the fire detector FD3 and the gain in the amplifying unit 72 provided in the test light receiving unit 70.
[0041]
If the light receiving glass G is not fouled (if the fouling rate D is 0%), the gain in the amplification unit 72 is multiplied by 1. If the fouling rate D of the light receiving glass G is 0% <D ≦ 50%, the gain If the contamination rate D of the light receiving glass G is 50% <D ≦ 75%, the gain is set to 4 times. In addition, if the pollution rate D of the light reception glass G will be 75% or more, the light reception glass D will be cleaned.
[0042]
Next, the operation of the fire detector FD3 will be described.
[0043]
FIG. 7 is a flowchart showing the operation of the fire detector FD3.
[0044]
First, usually, fire detection is performed periodically (S22), and when a test control signal is received from a disaster prevention panel (not shown) (S12), the contamination of the light receiving glass G is measured. That is, the test light emission control unit 61 is controlled (S13), the light emitting element 62 emits light, and this light is received by the light receiving element 71 through the light receiving glass G, and the output signal of the light receiving element 71 is passed through the amplifying unit 72. To the CPU 53 (S14). At the same time, the output signal of the light receiving element 51 is sent to the CPU 53 via the amplifiers 52 and 52a (S15).
[0045]
First, using the output signal from the light receiving element 51, the CPU 53 determines the presence of external light noise (S16). That is, the light receiving element 71 for detecting dirt faces the light emitting element 62 and sufficiently receives the light emitted from the light emitting element 62, but the light receiving element 51 for monitoring the fire naturally emits light because it is necessary to look at the monitoring section. It does not face the element 62 and the light emitting element 62 hardly receives light.
[0046]
However, if there is external light noise in the monitoring section, the light receiving element 51 for monitoring the fire generates an output signal, and at the same time, the light receiving element 71 for detecting dirt also faces the outside of the light receiving glass G. Because of this, output by external light noise is performed.
[0047]
Accordingly, whether or not the light receiving element 71 detects external light noise is determined from the output signal of the light receiving element 51 (S16). If there is external light noise, a predetermined waiting time is waited (S20). The test operation is performed again (return to S13). Periodic fire detection is also performed during this waiting time (S21). If the light receiving element 51 does not detect external light noise, the CPU 53 calculates the degree of contamination of the light receiving glass G using the output signal from the light receiving element 71 (S17).
[0048]
When the degree of contamination of the light receiving glass G is equal to or greater than a predetermined amount (S18), the gain of the amplification unit 52 of the fire detection unit 50 is increased (S19), and the sensitivity corresponding to the contamination is maintained.
[0049]
That is, if the contamination rate (dimming rate) D of the light receiving glass G is 0%, the gain of the amplification unit 52 of the fire detection unit 50 is set to 1, and the contamination rate D of the light receiving glass G is greater than 0% and 50%. If it is within the range, the gain of the amplifying unit 52 is set to 2, and if the contamination rate D of the light receiving glass G is greater than 50% and within 75%, the gain of the amplifying unit 52 is set to 4.
[0050]
By the way, in the conventional flame detector, the gain of the amplifying unit corresponding to the amplifying unit 52 is always constant, that is, the gain of the amplifier when the light receiving glass is less fouled when the light receiving glass is heavily fouled. As large as the gain of the amplifier.
[0051]
However, in the fire detector FD3, when the light receiving glass G is less fouled, the gain of the amplifying unit 52 is reduced, so that the output current of the amplifier 52 is small, and therefore the power consumption in the amplifier 52 is small. There is.
[0052]
Further, in the fire detector FD3, as shown in FIG. 6, there is an advantage that the dynamic range of the amplifier 52 is larger as the contamination of the light receiving glass G is smaller.
[0053]
The light receiving element 51 is an example of a detection element that detects radiation from a flame through the light receiving glass, the amplifier 52 is an example of an amplification circuit that amplifies the output signal of the flame detection element, and the CPU 53 This is an example of flame discrimination means for discriminating the presence of flame based on the output signal of the amplifier circuit. The CPU 53 and the gain switching control unit 54 increase the gain of the amplifier circuit as the degree of contamination of the light receiving glass advances. It is an example of the gain adjustment means to do.
[0054]
Further, in the operation of the fire detector FD3, the output of the light receiving element 71 is canceled by detecting again after the waiting time in the presence of external light noise when calculating the degree of contamination. The operation (S22) may be entered to wait for the next test control signal, or the output signals of the light receiving element 71 and the light receiving element 51 may be continuously received without providing a waiting time. Good.
[0055]
【The invention's effect】
According to the first and second aspects of the present invention, when the function of the flame detector is confirmed and sensitivity correction is performed, the function of the flame detector is adequate even if external light noise such as light from a rotating lamp is received. In addition, there is an effect that the sensitivity of the flame detector can be appropriately corrected.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a flame detector FD1 according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the embodiment.
FIG. 3 is a diagram showing the frequency characteristics of a fire monitoring narrowband filter 12 and the frequency characteristics of a dirt detection narrowband filter 15;
FIG. 4 is a block diagram showing a flame detector FS2 according to a second embodiment of the present invention.
FIG. 5 is a circuit diagram showing a fire detector FD3 according to a third embodiment of the present invention.
6 is a diagram showing the relationship between the contamination rate of the light receiving glass G in the fire detector FD3 and the gain in the amplifying unit 72 provided in the test light receiving unit 70. FIG.
FIG. 7 is a flowchart showing the operation of the fire detector FD3.
[Explanation of symbols]
FD1, FD2 ... Flame detector,
11: light receiving element,
SW ... switch,
12 ... Narrow band filter for fire monitoring,
13 ... Amplifier circuit,
14: Smoothing circuit,
15 ... Narrow band filter for detecting dirt,
31 ... A microcomputer for fire determination control,
41 ... light emission control circuit,
42. Light emitting element for detecting dirt,
FD3 ... Fire detector,
50: Fire detection unit,
52. Amplification part,
53 ... CPU,
54 ... Gain switching control unit,
G: Light-receiving glass.

Claims (2)

A light receiving element installed inside the light receiving glass;
A fire monitoring narrow band filter having a flame fluctuation frequency characteristic and inputting an output signal of the light receiving element;
Flame discrimination means for discriminating the presence of a flame based on the output signal of the fire monitoring narrowband filter;
A dirt detecting light-emitting element installed outside the light-receiving glass and facing the light-receiving element;
A fouling detection narrow band filter having a frequency characteristic different from the flame fluctuation frequency characteristic and receiving an output signal of the light receiving element;
A contamination degree detecting means for detecting the contamination degree of the light receiving glass based on an output signal of the contamination detection narrow band filter when the contamination detection light emitting element emits light;
Switching means for switching the destination of the output signal of the light receiving element to the narrow band filter for fire monitoring or the narrow band filter for dirt detection;
A flame detector characterized by comprising: A fire monitoring light receiving element installed inside the light receiving glass for detecting radiation from the flame;
A fire monitoring narrow-band filter that has a flame fluctuation frequency characteristic and inputs the output signal of the fire monitoring light-receiving element;
Flame discrimination means for discriminating the presence of a flame based on the output signal of the fire monitoring narrowband filter;
A dirt detecting light emitting element installed outside the light receiving glass;
A dirt detecting light receiving element installed inside the light receiving glass and facing the dirt detecting light emitting element;
A dirt detection narrow-band filter having a frequency characteristic different from the flame fluctuation frequency characteristic and receiving an output signal of the dirt detection light receiving element;
A contamination degree detecting means for detecting the contamination degree of the light receiving glass based on an output signal of the contamination detection narrow band filter when the contamination detection light emitting element emits light;
A flame detector characterized by comprising:

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